Method of producing aryl phosphorus oxydichloride



Patented Sept. 27, 1949 METHOD OF PRODUCING ARYL PHOS- PHORUSOXYDICHLORIDE 7 Arthur Dock Fon Toy, Chicago, Ill., assignor to VictorChemical Works, a corporation of Eli-- nois N Drawing. ApplicationNovember 14, 1945,

' Serial No. 628,669

12 Claims. (01. 2( i0543) vention aromatic phosphorus oxydichlorides maybe produced by simultaneous production of these compounds and phosphorusoxychloride from the corresponding aromatic phosphorus dichloride.

The new process involves the reaction of the arm matic phosphorusdichloride with chlorineand phosphoric anhydride; Thereaction takesplace substantially in accordance withthe following equation: r

In general the process comprises forming a slurry of finely dividedphosphoric anhydride in the aryl phosphorus dichloride, preferably inliquid form, and then chlorinating this mixture by bubbling in gaseouschlorine, The chlorination. is carried out in a vessel e uipped withagie tator and a reflux condenser. The chlorine is added at such a ratethat the reaction heat maine tains a suitable refluxing temperature forthe phosphorus oxychloride component of the products. A suitabletemperature is of the order of 125 150 C. When the chlorination iscompleted and no further heat of reaction is produced, the addition ofchlorine is stopped. The charge is then heated by the application ofexternal heat to distill off the phosphorus oxychloride. The residualliquid product is substantially pure aryl phosphorus oxydichloride whichmay be further purified by distillation under Vacuum.

The aryl phosphorus oxydichlorides are valuable intermediates for use inthe synthesis of number of organic phosphorus compounds containingcarbon to phosphorus bonds such as phosphonic acids, esters, resins,etc.

As an example of the process, 1611 grams (9 moles) of phenyl phosphorusdichloride was placed in a three-necked flask equipped with a refluxcondenser, stirrer, thermometer, and chlorine inlet. 511 grams (3.6moles) of finely divided phosphoric anhydride was added and slurriedwith the phenyl phosphorus dichloride. Chlorine gas was then passed intothe slurry at a rate suflicient to cause the heat of reaction tomaintain a temperature sufficiently high to give a steady refluxing ofthe phosphorus oxychlcride formed in the reaction. C. was employed inthe presentexample. After about three to four hours the temperaturedropped, indicating completion -of .thechlorination. The addition ofchlorine was discontinued and the flask heated externally to distill offthe phosphorus oxychloride. A total of 911 grams was recovered,representing a 99.2% yield and recovery of the by-product phosphorusoXychloride. The liquid phenyl phosphorus oxydichloride remaining in theflask was then recovered by distillation in vacuo, "1550 grams ofsubstantially pure phenyl phosphorus oxydichloride, boiling at 137138 C.under 15 mm. pressure, was recovered,*representing a yield of 88.4%. Anyexcess phosphoric anhydride remains in the flask and may be used againas part of the next charge. An excess of phosphoric anhydride is notrequired for the reaction, but does function in speeding up thetimerequired for completing the chlorination.

Tolylphflsphorus oxydichloride was prepared by placingin a three-neckedflask equipped with a stirrer, thermometer, and condenser, 200 g. oftolylphosphorus dichloride and 54 g. of phosphoric anhydride. The amountof phosphoric anhydride includes about ten percent excess over thatrequired by the equation Into this slurry was bubbled a steady stream ofchlorine gas while maintaining a temperature of about 35 to 40 C..After;2 hours the reaction was complete as indicated by the drop intemperature while continuing the addition of ch10- rine. The addition ofchlorine was stopped and the liquid reaction mixture distilled atatmospheric pressure to remove the phosphorus oxychloride, and. thenunder reduced pressure to distilloff the tolylphosphorus oxydichlorideproduct which had a boiling point of 140 to 142 C. at 11 mm. pressure.The yield of the product was g. (87.5% of theory). The yield ofby-product phosphorus oxychloride (POC13) was 90 grams (85% of theory).

Chlorophenylphosphorus oxydichloride was prepared using substantiallythe same procedure as in the preceding example. 200 g, ofchlorophenylphosphorus dichloride and 50 g. of phosphoric anhydride werechlorinated with an excess of chlorine gas. The chlorophenylphosphorusoxydichloride product recovered had a A temperature of about boilingpoint of Hi l-105 C. at 4-5 mm. pressure. The yield was 192 g.representing 88% of theoretical.

The process of the second preceding example (tolylphosphorusoxydichloride) was repeated except that the chlorination was carried outat a temperature of about 145 C. induced by the heat of reactionresulting from a more rapid addition of the chlorine gas. In thisexample 150 g. tolylphosphorus dichloride and 40 g. of phosphoricanhydride were employed. After the chlorination was completed theproduct was fractionally distilled, first under atmospheric pressure toremove the phosphorus oxychloride, then under reduced pressure to obtainthe tolylphosphorus oxydichloride product. The yield was 140 g. or

91.7% of theoretical. The boiling point of the product was 140-142" C.at 11-12 mm.

The foregoing detailed description given for clearness of understandingonly, and no unnecessary limitations should be understood therefrom.

What I claim as new, and desire to secure by Letters Patent, is:

1. The process which comprises reacting an aryl phosphorus dichloridewith phosphoric anhydride and gaseous chlorine to produce thecorresponding aryl phosphorus oxydichloride and phosphorus oxychloride.

2. The process of making an aryl phosphorus oxydichloride whichcomprises adding an excess of phosphoric anhydride to an aryl phosphorusdichloride and passing in gaseous chlorine to produce the correspondingaryl phosphorus oxydichloride and phosphorus oxychloride, and separatingthe phosphorus oxychloride therefrom by distillation, said chlorinebeing passed in at such a rate as to maintain a refluxing temperaturefor the phosphorus oxychloride.

3. The process which comprises reacting phenyl phosphorus dichloridewith phosphoric anhydride and gaseous chlorine under conditions toproduce phenyl phosphorus oxydichloride and phosphorus oxychloride.

4. The process which comprises reacting at approximately 125150 phenylphosphorus dichloride with an excess of phosphoric anhydride and gaseouschlorine to produce phenyl phosphorus oxydichloride and phosphorusoxychloride, and separating the phosphorus oxydichloride bydistillation.

5. The process of making phenyl phosphorus oxydichloride which comprisesforming a slurry of phenyl phosphorus dichloride and an excess of hasbeen 1 residual material by vacuum distillation.

6. In the manufacture of phenyl phosphorus oxydichloride from phenylphosphorus dichloride by the addition of phosphoric anhydride andchlorine gas, the step of adding chlorine gas to -a phenyl phosphorusdichloride-phosphoric anhydride mix at a I rate sufficient to maintain atemperature of to C.

'7. The process of claim 1 in which the aryl phosphorus dichloride istolylphosphorus dichloride.

8. The process of claim 1 in which the aryl phosphorus dichloride ischlorophenylphosphorus dichloride.

9. The process which comprises reacting at approximately 125-150 'C. anaryl phosphorus dichloride with phosphoric anhydride and chlorinesupplied from gaseous chlorine to produce the corresponding arylphosphorus oxydichloride and phosphorus oxychloride.

10. The process of making an aryl phosphorus oxydichloride whichcomprises adding an excess of phosphoric anhydride to an aryl phosphorusdichloride and passing in chlorine gas to produce the corresponding arylphosphorus oxydichloride and phosphorus oxychloride, and separating thephosphorus oxychloride therefrom by distillation, said reaction beingmaintained at a temperature of approximately 125to 150 C.

11. The process which comprises reacting at approximately 125150 C.phenyl phosphorus dichloride with phosphoric anhydride and chlorinesupplied as a gas to produce phenyl phosphorus oxydichloride andphosphorus "oxychloride.

12. The process ofrnalring an aryl phosphorus oxydichloride whichcomprises formin a slurry of aryl phosphorus dichloride and an excess ofphosphoric anhydride and passing chlorine gas into the slurry until thephosphorus dichloride has been substantially converted to the arylphosphorus oxydichloride with the formation of phosphorus oxychloride,separating the phosphorus oxychloride, and then removing the aryl phos-'phorus oxydichloride from the residual material.

ARTHUR; DOCK FON TOY.

No references cited.

